Introduction: 30 Min Automatic Drawer Light
Welcome to my first Instructable!
Although this concept is basic, I couldn't find an Instructable so I thought I would put one up. I hope you like it.
Everyone has at least one drawer or cupboard that can use a little more light. This simple, cheap project will add one with minimal parts and effort. Let's get started!
Step 1: Materials
1 Reed Switch
1 White LED (3 mm or 5 mm)
1 Coin cell battery holder
1 Coin cell battery
Foam core craft board
Stick tack (blue stuff in my photo)
Soldering iron (not shown)
Hot glue gun (optional - not shown)
I got a sheet of craft board for about $1. It has a foam core sandwiched between heavy paper. You only need a small square, the size of your battery holder.
I used one common fridge magnet and one neodymium (rare earth) magnet. I used whatever I had around the house. As long as one magnet is stronger than the other and the weaker one is still strong enough to trigger the switch, you're good. Also, the stronger magnet will be attached to the drawer or cupboard face. For my prototype, I didn't bother removing the magnet from the plastic bit.
Step 2: Prepare the Switch
The key to this is the reed switch. I got mine on eBay. I thought the most difficult part would be orienting the switch, but I found it to be fairly forgiving. In the final step, you can adjust the position of the light mechanism to get it to actuate properly. Try to bend the leads so the switch internally opens and closes front-to-back like our drawer. If you look closely, you should be able to see a small gap where the switch is open and the wires are not touching. Be careful bending the leads as the reed switch is (usually) enclosed in glass.
You might be able to hot glue this together but I ended up soldering it. It doesn't matter if the LED is touching the positive terminal on the battery holder or the negative, just make sure you have it flipped the right way around. In the photo, positive is at the top and flows though the reed switch to the positive (longer) lead on the LED. The other leg of the LED is soldered to the negative on the battery holder.
Step 3: Finish
- Flip the battery holder over and bend the LED up.
- Pop in the battery and hold a magnet near the switch. The LED should turn on.
- Attach the weaker magnet to the back of the battery holder. I attached mine on the outside of the craft board. You may have to experiment a little due to variations in the magnets you're using. If your magnet is too weak, it may not penetrate the craft board to turn the light on.
- Attach the battery holder to the craft board. Hot glue is great here but some stick tack to get it installed and tested quick. Trim the craft board to size.
- If you didn't attach the magnet directly to the battery holder, attach it to the craft board.
Step 4: Install
All that's left to do is install the light/battery holder and the rare earth magnet in your drawer!
Use some stick tack to attach the device inside your drawer with the switch facing towards you. The LED is at the back. Don't permanently attach it until you get it positioned so the light turns on and off correctly. I'm mounting to a smooth surface so i will probably leave the stick tack if it holds up.
Attach the rare earth magnet (or your stronger one) to the inside of the drawer face, lining up the magnet. You will have to play around a little, moving the the battery holder forward or backwards, or rotate it so the light turns off when the drawer is closed and on when it's open.
The weaker magnet is positioned to turn the switch on, but with the drawer closed, the stronger magnet on the drawer face counteracts the weaker magnet and keeps the switch open and the light off. Opening the drawer moves the stronger magnet away and the weaker magnet can then do its job and turn on the light.
Now you can get a midnight snack without turning on the kitchen lights!
Thanks to the Instructables community for all the awesome projects and inspiration. Please vote for me in the Make it Glow contest if you like this Instructable.